They probably freak out a lot because everything is out to destroy them... everything is bigger than them.... But they're probably really smart to survive so long. They're probably geniuses in their own fields.
I doubt they actually think, if you look at their brain structure, they lack anything but basic survival instinct. They eat, sleep, fornicate, crap, and move towards or away from stimuli compulsively. When they don't need to do any of those things, they just sit there. That's how they are wired, they just plain lack the brain structures for emotion or thought.